On August 23, 2013, OSHA issued a Notice of Proposed Rulemaking designed to reduce the permissible exposure limit (PEL) associated with silica dust exposure. OSHA is proposing a new PEL for respirable crystalline silica (quartz, cristobalite, and tridymite) of 50 μg/m3 in the general industry, construction, and shipyard sectors, a standard anywhere from two to five times more stringent than current PELs that date back to 1971.

According to OSHA’s Fact Sheet, “about 2.2 million workers are exposed to respirable crystalline silica in their workplaces. The majority of these workers, about 1.85 million, are in the construction industry. Exposures occur when workers cut, grind, crush, or drill silica-containing materials such as concrete, masonry, tile, and rock. About 320,000 workers are exposed in general industry operations such as brick, concrete, and pottery manufacturing, as well as operations using sand products, such as foundry work and hydraulic fracturing (fracking) of oil and gas wells. Workers are also exposed during sandblasting in general industry and maritime workplaces.”